Method and means of mixing concrete



March 16 ,1926. r

M. FLETCHER METHOD AND MEANS OF MIXING CONCRETE.

Filed July l4 1925 2 Sheets-Sheet 1 INVENTOR Maiihews'fieicller 'ATTo EYMarch 16 192 6.-

- 1 ,577,218 M. FLETCHER METHOD AND MEANS OF MIXING CONCRETE Filed July14, 1925 2 Sheets-Sheet 2 INVENTOR Mazihewsilei'cken 9 ATTORNEY PatentedMar. 16, 1926.

uN TED srA'rss 'MA 'rrrnws FLETCHER, or INDIAN-seems, INDIANA;

' METHOD AND MEANS OF MIXING CON CRETE Application filed July 14, 1925.Serial No. 43,631.

To all whom it may concern:

' Be it known that I, MATTHEWS FLn'roHnn, a citizen of the UnitedStates, residing at lndianapolis,-in the county of Marion and State ofIndiana, have'invented certain new and-useful Improvements in Methodsand Means of Mixing Concrete, of which the fol- "lowing is aspecification.

My invention relates to a method of mixing concrete and a mechanism forcarrying out such-method and it is an object thereof to provide a devicein which the process of mixing shall be a rapid and violent stirringaction applied to a rapid and continuous succession of small batches ofmaterials in place of the customary process of mixing in which slowtumbling and stirring action is applied to j a slow repetition ofcomparatively large batches of materials.

The common method of producing concrete by machine is to load 'a batchof ingredients into a slowly revolving cylinder or drum'where the massis mixed by tumbling, discharged, and the process'lrepeated with anotherbatch; a The drum must' revolve slowly inorder to prevent simplywhirling the mass without mixing, and consequently the time required tothoroughly mix a batch is practically thesame for large and smallmachines. Tl1' advantages of 7 rapid and violent agitation to secureintimate mixing and adhesion of cement are well known, but heretoforethese advantages have not been obtained generally in'a portable machineof commercial capacity on account of the struc tural and mechanicaldifficulties attending the rapid and violent agitation of the heavysemi-liquid mixture of concrete in. large quantities. My methodcontemplates overcoming these diflicultiesby greatly reducing the sizeof the batch or unit of production, assembling a rapid succession orcontinuation'of batches, and rapidly mixing them in and dischargingthemfrom a small machine of violent action.

Among other advantages of 111y-1netliod and device may be mentioned thefact that they produce an intimate mixing and ad- 5 hesion of cement toother particles with consequent density and strength in the ultimateconcrete, the fact that they provide for accurate control of theproportions of the materials entering into themixture, the .fact

- that they-provide for the conimingling of the solid materials inpredetermined constant,- proportion before entering the final mixinprocess, and the fact that they provide for the production of concretemixture in a practically uninterrupted flow with consequent-largeaverage output per unit of time. Q r V Referring to the accompanyingdrawings which are made a part hereof and on which similar referencecharacters indicate similar parts, I

Figure 1 is a plan of a mechanism constituting a preferred embodiment ofmy invention,

,. Figure 2, a side elevation partly in section, Figure 3, a sectiononline 33 of Fig.1, f Figure 4, a detailof a part as seen from the rightin Figure. 3,, 1

Figure 5, a section at right angles to Fig with modifications ofcertain/parts, and a Figure 6, a fragmentary section on linev 6-6 0fFigure 5. I V In the drawings reference characters 10, 11 and 12indicate separate bins for different solid ingredients, said bins beingindicated in the present embodiment of the invention and for the presentpurpose, as containing respectively, sand, gravel and cement.

Each bin is shown as having an outletat its lower end as indicated at 13by'means of which the material in the corresponding bin is'permitted toflow down upon the'upper run of a conveyor belt 14: in a'continuousstream, and this material forms a continuous ridge or stream on the beltin the channel between two of a series of partitions or walls '15supported above and extending along thebeltl l. Each of thechanncls'betweenpairsof partitions 15 is provided with a gate 16adjustable vertically and held in position by any suitable means, whichgates serve to limit adjust-ably the 'amount of material which will moveforward with the coin veyor; in the respective channels, therebyproviding a means'of proportioning the materials in any ratio desired.The and arrangement of bins,.the inclination of the conveyor, thedistance the, conveyor travels and all such minor details may be variedto suit particular circumstances or preferences.

Another conveyor 1'7, which may convennumber iently be referred to as asweeper, is provided adjacent to the forward end of the conveyor 14; andthis secondary conveyor or sweeper provided with brushes or blades 18 atsuitable intervals in its length and so placed and guided that thebrushcsor blades or similar suitaldc devices 18 will travel in aconstant path across the upper run of the primary conveyor lat and alonga trough 20 (Fig. 3) extending beyond its edge, thereby carrying batchesof commingled materials oil the primary ctmveyor, through the trough 9t)and into the hopper 21. In this way, it will be seen that the brushestake a cross section of each stream of material and so carry suitableincrements of all materials which make up the mixture. The sweeper l7 isregarded as carrying successive small batches of commingled materials tohopper 21 where they may he allowed to accumulate in a mass theingredients of which are nearly uniformly proportioned throughout. Or itmight be regarded as operated step by step and provided with morepositive batchconveying means whereljiy the successive small batcheswould be more or less independently fed to a mixing device or series ofdevices. A pipe 22 with a valve .23 provides a means of adding water tothe materials in the hopper 21.

A mixing device suitable to accomplish the final mixing oil thecommingled solids with *ater or other suitable liquid islocated beneathan opening; in the bottom of hopper 21. My mixing device consists of avertical passage or clunnber formed by a stationary casing 2a whichforms with the hopper a device shaped approximately like an hourglassand is oi? circular cross section. In this chamber an agitator 25 israpidly revolved by means oi. a. shaft which preferably is concentricwith the vertical axis. of the chamber and which may enter the chamberfrom above through the opening in the bottom of hopper 91 without thenecessity of providing a striding-box, all as shown in Figs. 2, 3 andThe chamber is open at the top to receive the mass or batches ofn'iaterials from the hopper and it extends downward to an open bowlorpan 27 provided to catch the mixture and thereby retard its rate of flowtl'irough the mixing chamber above in order that it may be re tainedlong enough to be subjected to thorough stirring by the agitator 5. Thepan 2T provided with an overflow spout 28 in the side or rin'i, or meansmay be provided for removing the mixture at the desired rate byintermittently tilting the pan or by undermining by means of a conveyor30 which may operate on the mass through an opening in the pan 2? at thebottom of the mixing; clunnber as shown by Fig. The cross sectional areaof the mixing chamber may be constant throughout its length as inastraight tube or it may be *aried, preterably increasing from top tobottom as shown. The agitator 25 consists of a series of blades,paddles, or irregularities 29 which can be rapidly revolved about avertical axis concentric with the axis of the chamber. The surfaces otthe. blades may be warped or formed into the shape of a screw to exert avertical pressure upon the mixture in addition to the stirring: action,and such a screw may extend up into the hopper 21 to provide a positivemeans of feeding the mass into the mixer. all as shown.

In the use of my device the materials are placed in separate hopperbills from which they pass to separate channels or chutes the bottoms ofwhich are formed by a moving conveyor belt apron or platform which dragsor pushes the materials through the channels and under grates orscrapers which areadjustcd to limit the quantities that will emerge inconstant proportion and will fol low on the conveyor in continuouslyformed parallel streams.

The parallel streams of materials in constant proportion are carriedforward. by the conveyor from which a cross section or batch of them isswept or pushed at. intervals by a series of flexible or pliant brushesor blades moved by a. belt or wheel revolving trainsversely to thedirection of the streams, and the batches thus formed are swept orpushed oil of the conveyor and into a hopper.

The batches of solid ingredients in predeterinined; proportion entereither intermittently: or contimiously into the hopper 21L into whichthe liquid ingredient (as water) also flows, and from which the massflows through a mixing chamber 24; where it is violently agitated andmixed as it flows by a series of rapidly revolving blades preferablyrevolving on a vertical axis concentric with the vertical axis of themixing chamher. The mixture is kept from simply falling through thechanlber, with consequent sepamtion ot the particles, by the pan or bowl2? which being placed beneath the botton'i opening of the mixing chambertends to support the mixture in the chamber and retards its rate of flowenough to allow time for proper mixing. The pressure exerted by theweight of incoming batches, which n'essure may be increased by thedownward pressure exerted by the screw-slmped agitator. causes thefinished mixture to flow or (to use a word that recently has come intogeneral use to accurately describe the action) to slmnyf over the edgeor brim ot the pan at the overflow spout. In place: of the slump processof discharging the finished mixtin'e, a more positive means ofdischarging by umlermining the mixture, or by intermittent- 1y tiltingthe pan may be provided and suit ably synchronized. The arrangement ofan agitator revolvingon an axis concentric with the vertical axis oi? amixing chamber of receiving parallel streams for circular horizontalsection allows of a very rapid rate of rotation. of the agitator Withoutpiling up the mixture .to one side (as occurs Where an agitator isrevolved rapidly 011a horizontal axis) and consequently the materialscan be subjected to very forceful stirring tvhich causes the particlesto collide with and impinge upon each-other with great violence andthereby to tend to,

each other and K to become thoroughly and intimately mixed in a veryshort time. The screw-shaped agitator and the flared? chamber provideadditional means by which even stiff mixtures (that is, mixturescontaining little or no excess water) may be forced through the mixingprocess. lhus is produced an intimate mixa ing and adhesion of cementwith consequent density and strength in the ultimate concrete.

It will be obvious to those skilled in the adhere to art that variouschanges may be made in my device without departing from the splrit ofthe invention and therefore I do not limit myself to what is shown inthe drawings and described in the specification but only as indicated inthe appended claims.

Having thus fully described my said in vention, What I claim as new anddesire to secure by Letters Patent, is t 1. A methodof mixing concreteWhich consists in simultaneously. and continuously moving sundryingredients in small parallel streams, disposed'laterally with relationto each other, and moving forward portions of the mass transversely ofthe path of movement of the streams to mix and discharge the same,substantially as set forth.

2. A, continuous process of mixing concrete or the like byproducingcontinuous slowly moving parallel streams of different solidingredients, and simultaneously hori Zontally and transversely ,mixingand feeding cross sectional increments of each stream into a mixingchamber, substantially as set forthQ i 3. The combination in a concretemixing machine of a hopper having a plurality 'of' partitions forming aplurality of bins, and conveyor disposed beneath said hopper for ofsolid material of different character therefro-i'n, substantially as setforth.

l. lhc combination in a concrete mixing machine of a hopper having aplurality of partitions forming a plurality of bins, a conveyor disposedbeneath said hopper receiving material of different character therefrom,means for feeding batches of material comprising a cross section of eachstream simultaneously into a chamber, means for add ing Water thereto,and a rotary agitator in the chamber, substantially as set forth.

5. A concrete mixer as in claim 3, with parallel streams of solidindependent means for adjusting the feed of solid material in eachstream, substantially as set forth.

6. A concrete mixeras in claim 8, com prising a conveyor belt forsupporting all of said streams of solid material, substantially as setforth.

7. A concrete mixer as in claim 3, comprising a conveyor belt forsupporting all of saidstreams of solid material, and means keepingthep'arallel streams separate, substantially as set forth.

.8. A concrete mixer comprising a plurality of bins for solid r aterial,means for feeding material in parallel horizontal streams from therespective bins, guiding means for separating the streams from eachother, gates for regulating the flow of ma terial in said streams, and amixingchamher for receivin such material substantiall a conveyor movabletransversely of the path of said streams, a mixing chamber to which saidconveyor carries increments of material from each of said streams, meansfor supplying Waterto said mixing chamber, and

agitating means for the mixture, substantially as set forth. I

12. A concrete mixer comprising a con veyor for feeding solid materialin parallel streams, a sweeper movable transversely of the path of saidstreams, brushes on the sweeper, a mixing chamber to Which said sweepercarries increments of material from each of said streams, means forsupplying Water to said mixing chamber, and agitating means for themixture, substantially as set forth.

13. A concrete mixer comprising means for feeding a parallel series ofstreams of solid material of different characteristics, a conveyormovable transversely of said feeding means, a trough in which saidconveyor travels, amixing chamber at the farther end of the trough,means for feeding Water to the mixing chamber, and a rotary agitator inthe mixing chamber, substantially "as set forth.

l layA. concrete mixer comprising means for f edingsolid material in pa"allel streams,

and conveying means movable transversely oi diii'rrnni solid ingrndiorigsinlnltnnuonsiy (hinnninn tho ingg'rndion'is Mid oonnnirnriing saiddnnnnod ingredients by moving them in n sidrn'isn diroriioin snhsinniinily as set forth.

16. A method of mixing concrete (.(Hl'lPliS- in;- providing rontinnmish'moving streams of diiim'nnil solid in 'redimlts, sinlnitnnoonsiych'nnniinn; tho i11 11 innln and connningling' said dnnnnm ingredientsby moving thnni in. n sidmviw direc-iion, nndi'hur :nrfter rapidly andviolvniiy agitating the uonnningind ingroijhvnhts n passing: Them inconhicr with rapidly riiintinp; hhnins, Sililftiifitiielii) an 90tforth.

.17. A prmsrssi oi mining coi'ioroio corn ing: i nvding relntii'oiysn'niii hatches of tho ingrndinnin in'io n hopper and downwnrdi paint annprighi running wrrw conveyor,

.i i hopper at :11]. i'inneez, and discharging :1 produlorniinvdmmntit'v of thn mixture from the ho) 101' by :1 shnnjnn notion n 3011the :1)-

L i r:

piicnfion of :i oorrespomiing amount of tho ingredients in the entrance0nd of the hopper, snhstnniinll as sot forth.

18. A conveyor coinprisiing' :1 heh; hni 'ingy; :1 continuous row ofbrushes at one side and n sci-ins of spaced brushes extending; ncronsthe bait from mid (:(niiinnons brushes, and :Riiifii'itllilY as setit'orih.

in winning whereof, I have hereunto Set my hnnd and seen] atIndi:innpolis, lfndinnn ihis 6th day of July, A. D. nineteen hundred nnd i \i'OlliiW-ihlfi.

MATIHEV S FLETGHE 1.

